J. Nannoplankton Res. 37 (1), 2017, pp.25–60 © 2017 International Nannoplankton Association
ISSN 1210-8049 Printed by The Sheridan Press, USA

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Calcareous nannofossils from the Eocene North Atlantic
Ocean (IODP Expedition 342 Sites U1403–1411)
Paul R. Bown*, Cherry Newsam
Department of Earth Sciences, University College London, Gower Street, London, WC1E 6BT, UK; *p.bown@ucl.ac.uk
Manuscript received 23rd June, 2016; revised manuscript accepted 7th December, 2016

Abstract Integrated Ocean Drilling Program Expedition 342 (June-July 2012) cored nine sites and 18 holes(Sites U1403–U1411) on the J-Anomaly and the Southeast Newfoundland ridges in the NW Atlantic Ocean. Thesesites recovered sections ranging from Pleistocene to upper Albian, but the expedition particularly focussed on therecovery of expanded Paleogene successions with high quality microfossil preservation. This was achieved bychoosing sites with thick packages of drift-type sediments on topographic highs that would maximise the preservationof carbonate. The expedition suceeded in recovering middle Eocene to lower Oligocene and upper Oligocene tolower Miocene high sedimentation rate sediment sequences with very well preserved microfossils. Highlights of the
expedition include the recovery of continuous Eocene/Oligocene and Oligocene/Miocene boundaries, a Cretaceous/
Paleogene boundary section with an intact spherule layer, and Cenomanian/Turonian section with a 44cm blackshale. Here, we describe notable aspects of the Eocene nannofossil record, including the exceptional preservationand the evolution of several important Eocene groups: Nannotetrina, the Sphenolithus furcatolithoides group, theReticulofenestra bisecta group and the Coccolithus gigas group. We also present a taxonomic overview of the Eocene
nannofossil assemblages from Sites U1403–1411, illustrating 164 taxa and describing 25 new species (Blackites
friedrichii, Blackites sextonii, Blackites subtilis, Calcidiscus scullyae, Clausicoccus norrisii, Coccolithus hulliae,
Coccolithus opdykei, Cruciplacolithus nishii, Helicosphaera prolixa, Holodiscolithus agniniae, Holodiscolithus
lippertii, Holodiscolithus liuii, Holodiscolithus whitesideae, Nannotetrina plana, Nannotetrina ruda, Neococcolithes
purus, Neococcolithes radiatus, Pontosphaera brinkhuisii, Pontosphaera hollisii, Pontosphaera romansii,
Pontosphaera wilsonii, Reticulofenestra magniscutum, Scyphosphaera interstincta, Semihololithus pseudobiskayae,
Syracosphaera octiforma) and five new combinations (Blackites inversus, Pontosphaera zigzag, Reticulofenestra
erbae, Reticulofenestra isabellae, Umbilicosphaera elliptica).

Keywords Paleogene, Eocene, Oligocene, Atlantic, taxonomy, calcareous nannofossils

1. Introduction
Integrated Ocean Drilling Program Expedition (IODP
Exp.) 342 (June–July 2012) cored nine sites and 18 holes(Sites U1403–U1411; Figure 1) on the J-Anomaly andSoutheast Newfoundland ridges in the NW Atlantic
Ocean, recovering a virtually complete composite section ranging from upper Albian to Pleistocene, representing 100Ma of Earth history (Figure 2). Moving
downhole, the youngest 15 million year portion of thisrecord (middle Miocene to Recent) is typically represented by thin Pleistocene foraminifer-rich sandy clay,
and thin, stratigraphically-short, sections of Pliocene
and upper Miocene clay, often with manganese nodules.
Below the middle Miocene, the stratigraphic histories ofthe sites fall into two distinct groups, corresponding to
the J-Anomaly ridge and SENR (Southeast Newfoundland ridge) locations.
The J-Anomaly sites typically comprise highsedimentation-rate lower Miocene to upper Oligocene
sequences, with occasional minor hiatuses, and lower sedimentation-rate Oligocene to Paleocene sequences. The
lower Eocene to Paleocene sequence is relatively condensed (Site U1406) and/or contains one or two minor

hiatuses (Site U1403 and U1406). Complete Miocene/
Oligocene boundary sections were recovered at sites
U1404 through U1406, and complete but lower sedimentation rate Oligocene/Eocene boundary sections at
Site U1404 and U1406. Site U1403 is the deepest site on
J-Anomaly ridge and recovered a lower Eocene throughupper Cretaceous sequence, with several key intervals,
including the early Eocene thermal maximum 2 (ETM 2),
Paleocene-Eocene thermal maximum (PETM) and Cretaceous-Paleogene (K/Pg) boundary event (Figure 2).
The SENR sites comprise short Pleistocene and
Neogene sequences overlying higher sedimentation-rate
Oligocene through Paleocene sections. The highest
sedimentation-rate, clay-rich drift sediments include middle Eocene sections at sites U1408 through U1410, and an
upper Eocene through Oligocene section at Site U1411.
These clay-rich sediments contain exceptionally wellpreserved calcareous microfossils, including glassy planktic foraminifers and a diverse range of fragile and small
nannoplankton. The carbonate-rich lower Eocene lithologies contain less well-preserved calcareous microfossils
but nevertheless provide a relatively continuous stratigraphic record. PETM-equivalent sequences are present at

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Bown, Newsam

Figure 1: Location map of the sites drilled during IODP Expedition 342

sites U1407 and U1409, but the stratigraphy is condensed
and/or includes minor hiatuses and, in the core of the event
interval, the sediments are indurated, silicified and include
chert beds. Site U1407 also recovered a long Cretaceous
sedimentary record from the upper Maastrichtian to upper
Albian, although a relatively large hiatus cuts out the lower
Maastrichtian and upper Campanian. Sedimentation rates
are low (0.15–0.41cm/k.y.), but there is a relatively continuous record from the lower Campanian through upper
Albian, including a striking Cenomanian/Turonian boundary black shale sequence representing OAE (Oceanic
Anoxic Event) 2, and an Albian-Cenomanian section lying
over shallow-water carbonate facies (Figure 2).
Initial biostratigraphic results are published in
Norris et al. (2014), and high resolution integrated
stratigraphic, isotopic and palaeoecological studies
are in progress. In this paper, we describe some notable aspects of the Eocene nannofossil record, including the exceptional preservation and the evolution ofseveral important Eocene groups: Nannotetrina, theSphenolithus furcatolithoides group, the Reticulofenestra bisecta group and the Coccolithus gigas group. We
also provide a taxonomic overview of the Eocene nannofossil assemblages from Sites U1407–1411, illustrating c.150 taxa and including the description of 25 new
species and five new combinations.
2. Material and methods
Nannofossils were viewed in simple smear-slides (Bown& Young, 1998), using transmitted-light microscopy(Zeiss Axiophot) in cross-polarised light (XPL) and phase
contrast (PC) at x1000–1600. Selected samples were also
examined in the SEM (scanning electron microscope;
JEOL Digital JSM-6480LV) in order to confirm the highquality preservation that is evident in the LM (light microscope). Here we report on the middle Eocene throughlower Oligocene sections from Sites U1407–1411, which
include the best preserved Paleogene nannoplankton.

3. Biostratigraphy
Semi-quantitative biostratigraphic data were generated
during Exp. 342 and initial results are given in Norris et al.
(2014), including range charts. In the Paleogene part of thesection the nannofossil biozonation of Martini (1971) wasused, and the Exp. 342 timescale, based on Gradstein et al.
(2012), is applied herein (see Norris et al., 2014, fig. F5).
4. Exceptional microfossil preservationin clay-rich drift sediments
One of the primary objectives of Exp. 342 was the recoveryof high accumulation-rate, clay-rich sediments containing
well-preserved microfossils suitable for geochemical andmicrofossil assemblage studies. Where drift sediments
were recovered, we observed calcareous microfossil preservation that was good and moderate to good, and significantly better than the quality of preservation that is
typical of most Paleogene deep-sea deposits. Furthermore,significant intervals of these drift successions contained
exceptionally preserved calcareous microfossils, including diverse, minute and fragile calcareous nannofossils(see Plates 1–15 herein) and glassy planktic foraminifera(Norris et al., 2014, Fig. F36). Such high quality preservation is usually only found in clay-rich, hemipelagic
shelf successions, and the recovery of stratigraphicallycontinuous and expanded middle Eocene through lower
Miocene successions with exceptional microfossil preservation was a significant success of the expedition.
5. Expedition 342 nannofossil
occurrences: preservation or ecology?
The recent discovery of many new Paleogene taxa in the
Tanzanian microfossil lagerstätte has led to re-evaluationof the taphonomic and ecological processes governing
the preserved fossil record of calcareous nannoplankton(Bown et al., 2008; Dunkley Jones et al., 2009). The contrasting shelf and ocean distribution records of many nannofossil taxa, being rare or absent in deep-sea sediments

Calcareous nannofossils from the Eocene North Alantic Ocean…

Figure 2: Summary of the stratigraphy recovered during IODP Expedition 342 (after Norris et al., 2014)

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Bown, Newsam

and common and/or diverse in hemipelagic successions,can be interpreted as predominantly a taphonomic signal,an ecological signal, or some combination of both factors(Bown et al., 2008). The Tanzanian lagerstätte is characterised by high abundances and/or diversity of Braarudosphaeraceae, Pontosphaeraceae, Rhabdosphaeraceae(especially Blackites), holococcoliths (e.g., Clathrolithus,
Holodiscolithus, Lanternithus), and rarer occurrences ofdeep-time representatives of Calciosoleniaceae (Calciosolenia), Syracosphaeraceae (Syracosphaera) and abundantGladiolithus. In addition, hemipelagic sediments tend tocontain far greater numbers of very small (<3µm) coccoliths, which are often numerically dominant (e.g., Gibbs
et al., 2006; Dunkley Jones et al., 2009; Bown, 2016; thiswork). Disentangling which is the prevalent control onthese distributions is difficult because the majority of deepsea sediments are either carbonate-rich or have undergone
dissolution, and are therefore rarely free from the overprintof strong diagenetic modification processes. The Exp. 342
sites provide new insight into this problem because theincorporation of a significant clay component has resulted
in the accumulation of hemipelagic-like sediments withimproved preservation potential but in a truly oceanic setting (3.0–4.0km current depth; 2.6–3.1km palaeo-depth at50Ma). Through much of the Paleogene and lower Neogene succession we are able to dismiss dissolution andovergrowth as a major factor controlling the presence orabsence of nannofossils, and so the predominant factor on
distribution is most likely the result of ecology. It should
also be noted that there is little evidence of any significant
microfossil reworking through these successions.
Braarudosphaeraceae. Braarudosphaeraceae is one
group in which there is a relatively straightforward explanation for their strongly skewed shelf-sea distribution,
because both extant and fossil forms are almost exclusively nertic, with rare oceanic occurrences explained byatypical events or environmental conditions (e.g. Kelly
et al., 2003). This is confirmed in the Exp. 342 sites,
which are virtually devoid of braarudosphaerids, with the
exception of:
1. a short mid-Cretaceous interval (Albian-Cenomanian)with Braarudosphaera africana at Site U1407 whereshallow water, initially reefal, conditions occurred
early in the site’s history;
2. very rare occurrences of Braarudosphaera bigelowii
in the post-K/Pg mass extinction recovery interval at
Site U1403; and3. a short interval, at the Oligocene/Miocene boundary ofSite U1405, which represents a period of unusual conditions with common Braarudosphaera and Micrantholithus (see Norris et al. 2014 for further details).

this may reflect the higher latitude position of the NW
Atlantic area, or, alternatively, the outer shelf setting of
Tanzania may have been richer in holococcoliths than the
open-ocean. There are one or two exceptions to this, however, with Zygrhablithus bijugatus common through muchof the Eocene succession, as it is in many other oceanic
sites, confirming its widespread distribution in shelfand oceanic successions alike (Schneider et al., 2011;
Gibbs et al., 2016). Also, Daktylethra unitatis is present
through the Exp. 342 middle to upper Eocene, and ranges
into the lower Miocene, extending the stratigraphic rangeof this taxon considerably. Lanternithus minutus, whichis common in Tanzania, is only sporadically present at
the Exp. 342 sites and never common.
Rhabdosphaeraceae. The occurrence of rhabdoliths in
the Exp. 342 material is comparable to the Tanzania succession, with several taxa common and consistently present,
e.g. Blackites amplus, B. tenuis, B. stilus and B. spinosus.
At least 12 of the 15 new rhabdolith taxa described fromthis stratigraphic interval in Tanzania (Bown, 2005; Bown
& Dunkley Jones, 2006), are also present in the NW
Atlantic (B. bullatus, B. flammeus, B. furvus, B. fustis,B. globulus, R. gracilenta, B. kilwaensis, B. ornatus,
B. rotundus, B. stilus, B. tortilis and B. virgatus) and three
more species are described herein (see below and Plates 8,
9, 15). This indicates that the rhabdolith group in general
was broadly distributed in the Eocene with neritic and oceanic occurrences.
Small coccoliths. The link between preservation ofsmall coccoliths and taphonomy is clearly demonstrated
by comparison of modern taxa with the Holocene fossil record, which typically lacks coccoliths with length<3µm (Young et al., 2005). When high quality nannofossil preservation is encountered in the fossil record thenthe presence of abundant, very small coccoliths is usually striking (Bown et al., 2008). This is confirmed in
the Exp. 342 material, in which small coccoliths (<3µm)
are dominant where preservation is good. In the middle
Eocene to lower Oligocene interval, these coccoliths are
predominantly reticulofenestrids, which typically makeup ~50–60% of the assemblage (see, e.g., Plate 13, figs
1–6). Small representatives of coccolithaceans (e.g. Coccolithus, Clausicoccus) may also be common (Pl. 13,
fig. 21; Pl. 14, fig. 9).
Other taxa. Other assemblage characterstics that arecomparable with the Tanzania successions include highdiversities in Pontosphaera, Scyphosphaera (Plates 6, 14)
and Helicosphaera (Plates 5, 14) (six new species
described herein), and the consistent occurrence of
Eocene representatives of Calcidiscus and Umbilicosphaera (Plate 4, 5).

Holococcoliths. In general, the Exp. 342 holococcoliths
are not as common or diverse as seen in the Tanzaniansuccession (Plates 10, 15), suggesting environmental factors play a role in their oceanic distribution. In this case,

6. Evolution of the genus Nannotetrina
Nannotetrina is a short-lived, middle Eocene nannofossil genus comprising around six species that are typicallylarge, three-dimensional nannoliths with square, cruciform

Calcareous nannofossils from the Eocene North Alantic Ocean…

29

Figure 3: Stratigraphic distribution and possible phylogentic relationships within Nannotetrina and related taxa. The timescale is from Norris et al.
(2014). Dotted vertical lines are uncertain stratigraphic ranges, horizontal bars indicate well constrained range base or top

or stellate outlines and four diagnostic raised ridges orcrossbars (see Figure 3 and Plate 7). In XPL the nannoliths
are typically dark yellow to brown, indicating construction
from few crystal units (at least four) that share high-angled
c-axis crystallographic orientation, i.e., the elements are
in extinction when lying flat. The unusual morphology of
Nannotetrina has led to a number of different suggestions
for their origin, ranging from nannolith ancestors, suchas Micula, to more straightforward origins within Eocene
coccolith groups, particularly from within the Zygodiscaceae. Several authors have discussed the Zygodiscaceae
ancestry (Bramlette & Sullivan, 1961; Perch-Nielsen,1985) and, specifically, that they originated as modified,enlarged central-area crossbar structures from which
the coccolith rim has been lost. Thickened and elevatedcrossbars are seen in both Neococcolithes and Chiphragmalithus in the stratigraphic interval preceding the appearance of the first Nannotetrina in Zone NP14 and so thereis good stratigraphic support for this hypothesis. Nannotetrina also have comparable crystallography to the crossbars of Neococcolithes and Chiphragmalithus, i.e., they

have high-angle c-axes. Unfortunately, the Chiphragmalithus group is poorly documented and stratigraphic ranges
are not well constrained, but they are reported from Zone
NP12 to NP14 (Bramlette & Sullivan, 1961; Shamrock &Watkins, 2012).
The link to the Cretaceous genus Micula was proposedby Romein (1979) and further discussed in Perch-Nielsen(1985) but there is little to support the idea as it is based on
the erroneous observation that Micula ranged consistently
through the Paleocene-Eocene, whereas these occurrences
are now considered to be reworking. Further, the cubiform
morphology of Micula is only very superficially similar
to Nannotetrina, with Micula structure comprising far
more numerous and complexly-intergrown crystal units
with variable crystallographic orientations (see for example Nannotax: http://www.mikrotax.org/Nannotax3/index.
php?dir=Mesozoic/Nannoliths/Polycyclolithaceae/Micula).
Expedition 342 nannofossil assemblages from Subzone NP14a include a range of morphotypes that appear
to represent transitional forms between Neococcolithes/
Chiphragmolithus and Nannotetrina (Figure 3 and30

Bown, Newsam

Plate 7). These assemblages include Neococcolithes
protenus coccoliths with typical simple, narrow, murolith rim and simple diagonal crossbars with all partsin near extinction in cross-polarized light (the R-unit
proximal wall unit is very reduced in Neococcolithes
and not visible in plan view in LM) (Pl. 7, figs 2–3).
Alongside these forms are Chiphragmolithus-like coccoliths and Nannotetrina-like liths, which appear torepresent transitional forms, as follows:
1. Chiphragmolithus acanthodes (Pl. 7, figs 4–12) –Neococcolithes-like but higher and larger with ragged
outlines and crossbars that extend across the rim to thecoccolith edge;
2. Chiphragmolithus calathus (Pl. 7, figs 13–15) – highand broadly-elliptical with high crossbars;
3. Nannotetrina ruda sp. nov. (Pl. 7, figs 16–20) – high,broad crossbars with reduced coccolith rim; and4. Nannotetrina plana sp. nov. (Pl. 7, figs 21–30) – relatively flat with broad crossbars and a basal disc/rim.
This proliferation of morphologies occurs over a relatively
short stratigraphic interval, immediately preceding theappearance of typical Nannotetrina cristata specimens (anelevated nannolith with four, relatively short crossbars/
ridges that widen towards their ends and sit on a basal,
plate-like structure: Pl. 7, figs 31–43), although several
forms do continue alongside Nannotetrina through theupper part of Zone NP14. The transition from Chiphragmolithus to Nannotetrina thus appears to have been associated with a radiation in Neococcolithes/Chiphragmolithus
coccoliths that include forms with Nannotetrina characters, such as reduction and loss of the murolith rim, lateraland vertical expansion of the crossbars and formation of abasal structure. In some of the early Nannotetrina forms,
multiple elements are evident in the basal disc in LM (e.g.
Pl. 7, figs 31–36), but this is not obvious in the younger
Nannotetrina specimens. The radiation also includes
Chiphragmalithus-like coccoliths such as C. acanthodesthat may be related to the Chiphragmalithus species
described from the older Zone NP12 interval, but perhaps
more likely represent homeomorphs within the Neococcolithes lineage. The disarticulated crossbars of Chiphragmalithus/Neococcolithes coccoliths are also documented
from this stratigraphic interval (e.g. Bown & Dunkley
Jones, 2012) and these may account for older records ofsmall ‘Nannotetrina’ (e.g., Bralower & Mutterlose, 1995).
After the appearance of N. cristata in Subzone
NP14b a number of specimens were observed that show
relict coccolith-rim and crossbar-like structures at thebase of the larger cruciform nannolith (Pl. 7, figs 37–43,
indicated by arrows on the images), providing further
support for these nannoliths being highly modified coccoliths that have lost much of or their entire coccolithrim. In these specimens, the relict rims are far smaller indiameter than the main cross structure. In later speciesof Nannotetrina, e.g., N. fulgens, the crossbars become

very long and form free-rays with reduced basal structure
or inter-arm fill (Pl. 12, fig. 12). In other species, suchas N. spinosa and N. pappii, additional ridges become
prominent giving the nannoliths a stellate appearance(Pl. 7, fig. 44).
7. Evolution of large middle Eocene
Coccolithaceae
The middle Eocene is characterized by the occurrence ofparticularly large (>12µm) coccolithacean coccoliths (seeexamples shown in Plates 3 and 12), which have been
included in a number of different genera including Coccolithus, Chiasmolithus, Cruciplacolithus and Birkelundia.
The generic assignment has been particularly influenced
by the relative importance placed upon central area structures, although modern representative of Coccolithus may
develop both transverse and axial crossbars. The middle
Eocene forms with wide central areas, relatively narrowtube cycles and diagonal crossbars are clearly correctly
grouped within Chiasmolithus (e.g. C. grandis, C. expansus: Pl. 3, figs 27–29; Pl. 12, fig. 4) but the generic affinityof other species is less clear cut. One group most-closely
resembles Coccolithus, with relatively narrow centralareas and broad tube-cycles but they have crossbars, usually axial, more rarely rotated. Although these taxa havesometimes been included within Cruciplacolithus, they are
now more frequently classified as Coccolithus (e.g. Coccolithus mutatus, Coccolithus staurion). The distinctive
marker species, ‘Chiasmolithus’ gigas also appears to be
one of these forms (original described as Coccolithus, but
subsequently reassigned based on the presence of diagonalcrossbars) and this is supported by new observations fromthe Exp. 342 material (Plate 3). These reveal a range ofmorphologies, comprising a lineage with early forms having broad, axial crossbars (assigned to C. staurion herein:
Pl. 3, figs 5–11) that give rise to coccoliths with rotated,asymmetric crossbars (named C. cf. C. gigas herein: Pl. 3,
figs 12–20, 23–24) and then to forms with diagonal crossbars that characterise C. gigas (Pl. 3, figs 21–22, 25–26).
The very large forms with axial and asymmetric crossbars
first appear near the Zone NP14–15 boundary, preceding
the appearance of C. gigas sensu stricto, which marks thebase of Subzone NP15b. This lineage strongly suggeststhat the ‘Chiasmolithus’ genus, as currently used, is polyphyletic and the species gigas is reinstated to its original
genus, Coccolithus, herein.
In addition to these very large forms, the middle
Eocene assemblages also contain a diverse range of large
Coccolithus coccoliths, including forms with crossbars(C. hulliae sp. nov., C. opdykei sp. nov.) and tranverse bars
(C. bipartoperculatus).
8. Evolution of the Sphenolithus
furcatolithoides group
Sphenolithus furactolithoides are highly distinctive middle Eocene sphenoliths (Zones NP15b-NP16), with spines

Calcareous nannofossils from the Eocene North Alantic Ocean…

that bifurcate but remain roughly parallel before diverging
again high-up on the spine (Plate 11). Shamrock (2010)
showed that this highly distinctive species was precededby forms with spines that diverge at a higher angle, lowon the spine, calling the species S. perpendicularis. The
excellent preservation of the Exp. 342 material reveals awide range of different morphotypes within this group,
including early spinose forms with very high-angle narrow
spines (S. cf. S. perpendicularis herein; Pl. 11, figs 1–3), avariety of S. perpendicularis types (Pl. 11, figs 7–13), andS. furcatolithoides variants with spines that converge ordiverge at different angles high-up along the spine (Pl. 11,
figs 15–22, 26). These spines can be extremely long, up to
25µm in length, and represent some of the ‘largest’ nannofossils ever found. The morphology of specimens close
to the first appearance of S. furcatolithoides itself suggestthat it may have evolved from a S. radians-like ancestor,
rather than the preceding widely-bifurcating forms (Pl. 11,
fig. 14).
9. Evolution of the Reticulofenestra
bisecta group
Reticulofenestrid coccoliths with closed central areas are
known through most of this groups history (lower Eocene
to Recent), but the appearance of common, medium- tolarge-sized forms with conspicuous (birefringent), distal central-area ‘plugs’ (the R. bisecta group of Bown &Dunkley Jones, 2012; Pl. 2, figs 20–44) is a highly distinctive stratigraphic signal occurring in lowermost Zone
NP17 (~40.36Ma) and close to the onset of the Middle
Eocene climatic optimum (MECO) event (Fornaciari
et al., 2010). However, the discovery of very rare andunusual R. bisecta-like coccoliths in Subzone NP15 (from~46 Ma) in the Exp. 342 material indicates that the group
had a cryptic origination at least six million years earlier
than this (Pl. 2, figs 25–44). These coccoliths, named
R. magniscutum sp. nov. herein, have very unusual, thickened, dome-like distal shields but possess the distinctive
central plug that is characterstic of the R. bisecta group.
It should be noted that this distinctive reticulofenestridgroup includes R. stavensis (>10µm) and R. bisecta(<10µm) but that these species are also placed in a separate genus, Dictyococcites, by some authors, and different species names, e.g. hesslandii and scrippsae, and size
categories are also applied (e.g. Agnini et al., 2014). In
addition, reticulofenestrids with simple, closed central
areas are also referred to as R./D. bisecta by some authors,
but we consider these to be separate taxa, though poorly
defined in current classifications (see below for further
discussion).
10. Systematic palaeontology
This section provides images of a representative selection of nannofossils from the IODP Exp. 342 Eocene sites(U1403–1411) in 12 LM plates and three SEM plates(Plates 13–15). The LM images are reproduced at constant31

magnification, and a 2µm scale bar is provided beside atleast one of the images on each plate. Taxonomic comments are only provided for notable taxa and the description of 25 new species. The taxonomic listing refers only
to species illustrated in the plates. Sample information isprovided using standard IODP notation (Hole-Core-Section, depth in cm in section). The descriptive terminology(including size classes) follows the guidelines of Young etal. (1997). The higher taxonomy follows the scheme forextant coccolithophores of Young et al. (2003) and, forthe extinct taxa, the scheme of Young & Bown (1997) andNannotax (http://www.mikrotax.org/Nannotax3). All new
taxonomic names are Latin, unless stated otherwise, andthe meaning is given in each case. Range information is
given for stratigraphic distributions in the Exp. 342 sites,
unless stated otherwise. Only bibliographic references notincluded in Perch-Nielsen (1985), Bown (1998) or Jordan
et al. (2004) are included in the reference list. A comprehensive list of bibliographic references can also be found on
Nannotax. The following abbreviations are used: LM – lightmicroscope, XPL cross-polarised light, PC – phase-contrast
illumination, L – length, H – height, W – width, D – diameter. Type material and images are stored in the Departmentof Earth Sciences, University College London.
10.1 Placolith coccoliths
Order ISOCHRYSIDALES Pascher, 1910
Family NOELAERHABDACEAE Jerkovic, 1970
emend. Young & Bown, 1997
Cyclicargolithus floridanus GroupPl. 1, figs 20–27; Pl. 13, fig. 7
Description: Subcircular to broadly elliptical reticulofenestrids with narrow central area and thin, imperceptible net (non-birefringent or lost).
Cyclicargolithus cf. C. abisectus (Müller, 1970) Wise,
1973
Pl. 1, fig. 25
Remarks: Used here for rare, but conspicuous, very large,
subcircular reticulofenestrids seen in the middle Eocene(e.g. Zone NP14) and similar in overall morphology to theyounger, Oligocene, species C. abisectus.
Cyclicargolithus floridanus (Roth & Hay, in Hay et al.,1967) Bukry, 1971
Pl. 1, figs 20–24; Pl. 13, fig. 7
Remarks: Used in a broad sense here for subcircular
reticulofenestrids with narrow central area. Specimens
with closed central areas are called Cyclicargolithus cf.
C. floridanus.
Cyclicargolithus cf. C. floridanus (Roth & Hay, in Hay
et al., 1967) Bukry, 1971
Pl. 1, figs 26–27
Remarks: Like C. floridanus but with closed central area.

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Bown, Newsam

Cyclicargolithus luminis (Sullivan 1965) Bukry 1971
sensu Shamrock & Watkins, 2012
Pl. 1, figs 28–29
Remarks: A distinctive, birefringent circular coccolith
occuring rarely in Zone NP14 to Subzone NP15a at Sites
U1407–1410. It is distinguised by relatively straight andaxial extinction lines. Shamrock & Watkins (2012) discuss
the differentiation between this and the older Cyclicargolithus parvus Shamrock & Watkins, 2012 species (previously called C. luminis in Bown, 2005).

Reticulofenestra bisecta group by around 6 m.y. The
species is very rare and so tracing the relationship between
R. magniscutum and R. bisecta has not been possible.
Dimensions: Holotype L = 8.5µm (Paratype L = 9.0µm).
Side view coccolith height ~6.5µm. Holotype: Pl.2, figs
25–28. Paratype: Pl.2, figs 31–36. Type locality: IODP
Hole U1408A, NW Atlantic Ocean. Type level: Middle
Eocene, Sample U1408A-14X-5, 63cm (Zone NP16).
Occurrence: Rare. Subzone NP15a-Zone NP16; IODP
Sites U1408, U1409 and U1410.

Reticulofenestra bisecta Group
Pl. 2, figs 20–44; Pl. 13, fig. 11
Description: Elliptical reticulofenestrids with central area
closed by a robust, conspicuous distal ‘plug’ (birefringent). In the type upper Eocene specimens this plug is adistal structure that is underlain by a proximal coarse grillof near radial laths. Thus defined, the stratigraphic rangeof the group is middle Eocene to lowermost Miocene. We
do not include reticulofenestrid coccoliths in which thecentral area is simply closed (e.g. see Pl. 1, figs 26–27;
Pl. 2, figs 17–19, 24), although these taxa are poorly
served by current reticulofenestrid nomenclature. Someauthors consider these forms to be ecophenotypic variants(e.g., Young, 1990, 1998), while others apply a paralleltaxonomy or broaden the taxononic concept of taxa suchas bisecta. Included species: R. bisecta, R. filewiczii,
R. magniscutum, R. stavensis.

Reticulofenestra stavensis (Levin & Joerger, 1967)
Varol, 1989
Pl. 2, fig. 22
Remarks: Greater than 10µm in length (the holotype is14µm).

Reticulofenestra bisecta (Hay et al., 1966) Roth, 1970
Pl. 2, figs 20–21; Pl. 13, fig. 11
Remarks: Less than 10µm in length (the holotype is 8µm).
Reticulofenestra filewiczii (Wise & Wiegand in Wise,
1983) Dunkley Jones et al., 2009
Pl. 2, fig. 23
Remarks: Appears at the same time as other membersof the R. bisecta group and is probably closely related
to these forms, differing only in having a small central
opening.
Reticulofenestra magniscutum sp. nov.
Pl. 2, figs 25–44
Derivation of name: From magnus, meaning ‘elevated’,and ‘scutum’ meaning shield, referring to the elevateddistal shield of this species. Diagnosis: Large, elliptical
reticulofenestrids with a thickened, dome-like distal
shield and central area filled with a plug. Differentiation:
Similar to other species of the Reticulofenestra bisectagroup but with an elevated, dome-like distal shield,
which is therefore highly birefringent (orange) in XPL
and frequently seen in side view (Pl. 2, figs 41–44).
Remarks: We have observed this species from a shortstratigraphic interval in the middle Eocene (Subzone
NP15a-lower Zone NP16), in an interval that predates
the common occurrence of other members of the

Reticulofenestra reticulata Group
Pl. 2, figs 3–16; Pl. 13, figs 12–16
Remarks: Typically circular reticulofenestrids with circular central area spanned by robust, visible net (birefringent). We currently include R. erbae (closed central-area),
R. isabellae (>12µm, broad tube-cycle and narrow centralarea); R. reticulata (<12µm, broad tube-cycle and narrow central-area) and R. westerholdii (medium-sizedwith less conspicuous tube cycle and inconspicuous or
no central net).
Reticulofenestra erbae Fornaciari et al., 2010 comb.
nov.
Pl. 2, figs 13–14; Pl. 13, fig. 12
Basionym: Cribrocentrum erbae Fornaciari et al., 2010,
p. 251, pl. 2, fig. 1, Stratigraphy, 7: 229–264.
Reticulofenestra isabellae Catanzariti et al. in
Fornaciari et al., 2010 comb. nov.
Pl. 2, figs 11–12; Pl. 13, fig. 16
Basionym: Cribrocentrum isabellae Catanzariti, Rio &Fornaciari in Fornaciari et al., 2010, p. 252, pl. 2, fig. 4,
Stratigraphy, 7: 229–264.
Reticulofenestra reticulata (Gartner & Smith, 1967)
Roth & Thierstein, 1972
Pl. 2, figs 7–10; Pl. 13, figs 13–15
Remarks: Used in a broad sense here for circular reticulofenestrids with moderately-wide to narrow central areas
and a visible net (birefringent). Very large forms (>12µm)
have been differentiated as R. isabellae (Pl. 2, figs 11–12)
by Fornaciari et al. (2010) and we informally differentiated forms with wide central areas (Pl. 2, figs 7–9) andspecimens with subcircular to elliptical outlines (Pl. 2, figs
3–6). Further subdivision may be warranted.
Reticulofenestra westerholdii Bown & Dunkley Jones,2012
Pl. 2, figs 15–16

Calcareous nannofossils from the Eocene North Alantic Ocean…

33

Remarks: This species has an inconspicuous or no central
net but is circular and is, in other respects, very similar toother species in the R. reticulata group.

Remarks: Used here in a broad sense for elliptical reticulofenestrids with elliptical and relatively open central
areas.

Reticulofenestra lockeri GroupPl. 1, figs 30–43; Pl. 2, figs 1–2; Pl. 13, fig. 10
Description: Elliptical reticulofenestrids with relatively
open central area and robust, visible net (birefringent).

Reticulofenestra hillae Bukry & Percival, 1971
Pl. 1, figs 44–45

Reticulofenestra daviesii (Haq 1968) Haq, 1971
Pl. 1, figs 33–36
Remarks: Differentiated from R. lockeri by a row of visible pores around the edge of the central net. Although thisspecies becomes conspicuous and abundant around the
Eocene/Oligocene boundary, it ranges down into the middle Eocene (Zone NP14) in the Exp. 342 material. Occurrence: Zone NP14–NP23.
Reticulofenestra lockeri Müller, 1970
Pl. 1, fig. 32; Pl. 13, fig. 10
Occurrence: Lower Eocene-lower Miocene (Zone NP13–
NN2).
Reticulofenestra cf. R. lockeri Müller, 1970
Pl. 1, figs 30–31; Pl. 2, figs 1–2
Remarks: Indeterminate forms with central areas that areeither narrower (Pl. 1, figs 30–31) or wider (Pl. 2, figs 1–2)
than the typical morphology.
Reticulofenestra macmillanii Dunkley Jones et al.,2009
Pl. 1, fig. 37
Reticulofenestra onusta (Perch-Nielsen, 1971) Wise,
1983
Pl. 1, figs 38–43
Description: Large to very large, distinctive elliptical reticulofenestrids with a wide central area spanned by a finely
perforate, weakly birefringent net. Differentiation: Distinguised from other R. lockeri group coccoliths by large
size, wider central area and clearly visibly fine perforations
across the net. Dimensions: L = ~11.0–12.5µm. Occurrence: Rare, but apparently restricted to Subzones NP15b-c;
IODP Sites U1409, U1410. Holotype from Zone NP15.
Questionable occurrences in Zone NP16 at Site U1410.
Reticulofenestra umbilicus GroupPl. 1, figs 8–19, 44–48; Pl. 12, figs 1–3;
Pl. 13, figs 8–9
Description: Elliptical reticulofenestrids with relativelyopen central area and thin, imperceptible net (nonbirefringent or lost).
Reticulofenestra dictyoda (Deflandre in Deflandre &Fert, 1954) Stradner in Stradner & Edwards, 1968
Pl. 1, figs 9–12; Pl. 13, fig. 8

Reticulofenestra minuta Roth, 1970
Pl. 1, fig. 8; Pl. 13, figs 1–4
Remarks: Used here in a broad sense for very small(<3µm), elliptical reticulofenestrids. Although they typically have open central areas, in SEM many specimens
are seen with closed central areas and at this size it may bedifficult to distinguish the different varieties in LM. Our
SEM observations suggest there is considerable diversityof form in this size range.
Reticulofenestra umbilicus (Levin, 1965) Martini &Ritzkowski, 1968
Pl. 1, figs 46–48; Pl. 12, figs 1–3; Pl. 13, fig. 9
Remarks: The first appearance of very large, >14µm,
elliptical reticulofenestrids (the species R. umbilicus) has
long been used as a distinctive stratigraphic marker (e.g.
Backman & Hermelin, 1986). In the Exp. 342 material
these sizes are attained by subcircular to elliptical reticulofenestrids (similar to R. wadeae and R. umbilicus) in
Subzone NP15b, around 3 m.y. prior to the level typicallycited for this biohorizon. Agnini et al. (2014) suggest thatthe use of the first common occurrence of R. umbilicus
may represent a more consistent horizon, above the last
occurrence of C. gigas.
Reticulofenestra wadeae Bown, 2005
Pl. 1, figs 13–19
Family PRINSIACEAE Hay & Mohler, 1967 emend.
Young & Bown, 1997
Girgisia Varol, 1989
Girgisia gammation (Bramlette & Sullivan, 1961)
Varol, 1989
Pl. 1, figs 5–7
Genus Towieus Hay & Mohler, 1967
Pl. 1, figs 1–4
Remarks: Toweius was one of the dominant placolithgroups of the late Paleocene to early Eocene but declined,
broadly coincident with the appearance and rise of the reticulofenestrid group in the early Eocene (zones NP12–13)(e.g., Agnini et al. 2006). The extinction of Toweius hasremained poorly constrained with reports ranging from
Zone NP12 (Bralower & Mutterlose 1995) to Zone NP15
(Perch-Nielsen, 1985). Relatively common Toweius coccoliths were documented in equatorial Pacific sites up to Zone
NP15 by Bown & Dunkley Jones (2012) and similarly we
see Toweius through to Subzone NP15b in the Exp. 342 sites(e.g. Site U1409), confirming this later extinction level.

34

Bown, Newsam

Toweius magnicrassus Bukry, 1971
Pl. 1, figs 3–4
Toweius pertusus (Sullivan, 1965) Romein, 1979
Pl. 1, fig. 1
Toweius patellus Bown, 2016
Pl. 1, fig. 2
Order COCCOLITHALES Haeckel, 1894 emend.
Young & Bown, 1997
Family COCCOLITHACEAE Poche, 1913 emend.
Young & Bown, 1997
Coccolithus biparteoperculatus (Varol, 1991) Bown &Dunkley Jones, 2012 Pl. 3, figs 30–31
Coccolithus crassus Bramlette & Sullivan, 1961
Pl. 2, figs 45–48
Remarks: Like C. pelagicus but with an unusually birefringent shield image in XPL. Occurrence: upper Zone
NP12–14a (Wei, 1993).
Coccolithus eopelagicus (Bramlette & Riedel, 1954)
Bramlette & Sullivan, 1961
Pl. 12, fig. 5
Coccolithus formosus (Kamptner, 1963) Wise 1973
Pl. 13, figs 19–20
Coccolithus hulliae sp. nov.
Pl. 4, figs 7–17
Derivation of name: Named after Celli Hull (University
of Yale, USA), Exp. 342 shipboard scientist, micropalaeontologist and palaeoceanographer. Diagnosis: Broadly
elliptical coccolith with Ericsonia-like shield image andmoderately wide central area (similar to shield width),spanned by conspicuous axial crossbars. Remarks: In
XPL the shields appear similar to Ericsonia (i.e. withbroad, bright tube cycle). Although Ericsonia coccoliths
are rarely and sporadically seen through the Eocene, these
are usually small, circular forms and we consider it most
likely that this species arose from a Coccolithus ancestor. Coccolithus hulliae appears to be stratigraphically
restricted to Zones NP14–15 in the Exp. 342 material.
This species may have been identified as Ericsonia insolita Perch-Nielsen, 1971 in Bralower & Mutterlose (1995)
and documented as having a first appearance in Subzone
NP14a. Differentiation: Distinguised from other Coccolithus and Ericsonia by its distinctive shield image in
XPL and moderately wide central area with conspicuous
axial crossbars. Dimensions: Holotype L = 8.4µm (Paratype L = 8.6µm). Holotype: Pl. 4, figs 16–17. Paratype:Pl. 4, figs 13–15. Type locality: IODP Hole U1407A,
NW Atlantic Ocean. Type level: Middle Eocene, Sample
U1407B-8-CC (Subzone NP14b). Occurrence: Subzone
NP14b-15b; IODP Sites U1407, U1408 and U1409. Site
U865, Pacific Ocean (Bralower & Mutterlose, 1995).
Coccolithus cf. C. hulliae sp. nov. var. 1
Pl. 4, figs 1–4

Remarks: Similar to C. hulliae but with a transverse bar.
Occurrence: Subzone NP14b–15b; IODP Sites U1407
and U1409.
Coccolithus cf. C. hulliae sp. nov. var. 2
Pl. 4, figs 5–6
Remarks: Similar to C. hulliae but with a moderatelywide, apparently vacant, central area (similar to shieldwidth). Occurrence: Subzones NP15b-c; IODP Site
U1408.
Coccolithus pauxillus Bown, 2010 Pl. 4, figs 29–30;
Pl. 13, fig. 21
Coccolithus pelagicus (Wallich, 1877) Schiller, 1930
Pl. 13, figs 17–18
Coccolithus gigas GroupPl. 3, figs 1–26; Pl. 12, fig. 7
Description: Large to very large Coccolithus coccoliths
with narrow to moderately-wide central areas spannedby crossbars that are conspicuous in light microscope.
Remarks: These coccoliths have previously been variously classified within the genera Cruciplacolithus,
Chiasmolithus and Coccolithus but appear to represent
a coherent lineage with stratigraphic range restricted tothe mid-part of the Eocene (Zones 14–16). The inclusionof these species within the genus Coccolithus is consistent with the extant Coccolithus species, which can also
produce central area bars and crosses. Included species:
C. gigas, C. mutatus, C. opdykei, C. staurion.
Coccolithus opdykei sp. nov.
Pl. 3, figs 1–4
Derivation of name: Named after Bradley Opdyke (The
Australian National University, Australia), Exp. 342 shipboard scientist and palaeoceanographer. Diagnosis: Large(<12µm) Coccolithus with a narrow central area (<shieldwidth) spanned by a broad, birefringent, axial to near-axial
crossbars that nearly fill the central area. Differentiation:
Smaller than C. mutatus, C. staurion and C. cf. C. gigas,
with broader crossbars than C. mutatus and C. staurion.
Similar to Cruciplacolithus opacus Shamrock & Watkins,
2012 but with a broader and brighter tube cycle in XPL.
Dimensions: Holotype L = 11.1µm (Paratype L = 9.6µm).
Holotype: Pl. 3, figs 2–3. Paratype: Pl. 3, fig. 1. Type
locality: IODP Hole U1407A, NW Atlantic Ocean. Typelevel: Middle Eocene, Sample U1407A-8H-CC (Subzone
NP14b). Occurrence: Subzones NP14b-15b; IODP Sites
U1407 and U1409.
Coccolithus gigas Bramlette & Sullivan, 1961 emend.
Pl. 3, figs 21–22, 25–26; Pl. 12, fig. 7
Emended diagnosis: Very large Coccolithus with narrow
to moderately wide central area spanned by thick crossbars which are diagonal or near diagonal in orientation,
making an angle of 30° or greater with the longitudinalaxis. Differentiation: Distinguished from Coccolithus cf.

Calcareous nannofossils from the Eocene North Alantic Ocean…

C. gigas by bar angles that are rotated greater than 30°
from the longitudinal axis. Typically the longitudinal bar
is closer to axial than diagonal in Coccolithus cf. C. gigas.
Occurrence: Subzone 15b.
Coccolithus cf. C. gigas Bramlette & Sullivan, 1961
Pl. 3, figs 12, 15–17, 19–20, 23–24
Description: Very large Coccolithus with narrow to moderately wide central area spanned by thick crossbars which
are rotated from axial by up to 29°. Differentiation: Distinguished from C. gigas by having near-axial to slightly
rotated crossbars rather than diagonal or near-diagonal
orientation, and from C. mutatus by the thicker crossbars.
Occurrence: Subzones NP15a-b (rare, questionable specimens in NP14b and NP15c); IODP Sites U1407, U1408,
U1409 and U14010.
Coccolithus mutatus (Perch-Nielsen, 1971) Bown, 2005
Pl. 3, figs 7, 13–14, 18
Description: Very large Coccolithus with moderately-broad central area spanned by narrow crossbars that are
axial or near axial. Occurrence: Zone NP14b-16; Sites
U1407–U1410.
Coccolithus staurion Bramlette & Sullivan, 1961
Pl. 3, figs 5–6, 8–11
Description: Very large (>12µm) Coccolithus with narrow
central area spanned by robust axial crossbars. Remarks:
The paratype has narrow bars and is probably a C. mutatusspecimen. The holotype is large in size (12–15µm) and wedistinguish smaller forms as Coccolithus opdykei sp. nov..
Synonym: Coccolithus insolitus (Perch-Nielsen, 1971)
Ladner & Wise, 2002. Occurrence: Zone NP13–17; Sites
U1407–U1410.
Chiasmolithus-Cruciplacolithus Group
Bramletteius serraculoides Gartner, 1969
Pl. 4, figs 18–20
Chiasmolithus expansus (Bramlette & Sullivan, 1961)
Gartner, 1970
Pl. 3, figs 27–29
Chiasmolithus grandis (Bramlette & Riedel, 1954)
Radomski, 1968
Pl. 12, fig. 4
Cruciplacolithus cruciformis (Hay & Towe, 1962)
Roth, 1970
Pl. 4, fig. 21
Cruciplacolithus nishii sp. nov.
Pl. 4, figs 22–28
Derivation of name: Named after Hiroshi Nishi (Tohoku
University, Sendai, Japan), Exp. 342 shipboard scientist
and micropalaeontologist. Diagnosis: Medium sized Cruciplacolithus with narrow shields and wide central areaspanned by narrow axial crossbars bearing a spine. Differentiation: Distinguised from other Cruciplacolithus by
the wide central area and spine-bearing cross – an unusual

35

feature amongst Cenozoic placoliths. Dimensions: Holotype L = 4.2µm (Paratype L = 4.3µm). Holotype: Pl.4,
fig. 27. Paratype: Pl.4, figs 24–26. Type locality: IODP
Hole U1408A, NW Atlantic Ocean. Type level: Middle
Eocene, Sample U1408A-4H-CC (Zone NP16). Occurrence: Zone upper NP16–17; IODP Site U1408, U1409.
Clausicoccus GroupPl. 4, figs 33–45; Pl. 14, figs 9–13
Remarks: A wide range of sizes are seen in this groupfrom very small (<3µm, e.g. Clausicoccus sp. small,Pl. 14, fig. 9) to very large (>12µm, e.g. Clausicoccus
vanheckiae and C. norrisii, Pl. 4, figs 38–43), but all arecharacterised by coccolithacean-type rims with narrow torelict distal tube cycles and a relatively coarsely-perforate
central area net. A number of SEMs suggests there is alsoa more finely perforate grill on the proximal side (Pl. 14,
fig. 13).
Clausicoccus fenestratus (Deflandre & Fert, 1954)
Prins 1979
Pl. 4, figs 35–36; Pl. 14, fig. 13
Clausicoccus fenestratus large (Deflandre & Fert,
1954) Prins 1979
Pl. 4, fig. 37
Remarks: Like C. fenestratus but large (~>9µm). Similar in size to Clausicoccus vanheckiae but with relatively
broader rim and narrower central area with fewer perforations. These forms become conspicuous for a short stratigraphic interval in Zone NP17 in the Exp. 342 material.
Clausicoccus cf. C. fenestratus (Deflandre & Fert,
1954) Prins 1979
Pl. 4, figs 44–45
Remarks: Like Clausicoccus fenestratus but the central,
perforate plate takes the form of broad axial crossbars.
Clausicoccus norrisii sp. nov.
Pl. 4, figs 40–43
Derivation of name: Named after Richard Norris (Scripps
Oceanographic Institute, USA), Exp. 342 co-chief scientist, micropalaeontologist and palaeoceanographer. Diagnosis: Large, broadly elliptical coccolithacean coccolithwith broad shields and moderately wide central area (similar to shield width) spanned by a plate that is indistinctly
perforate and crossed by strong diagonal extinction lines.
The bright inner cycle is relatively indistinct. Remarks:
Specimens of this species have previously been assigned
to the species ‘Coccolithites’ cribellum Bramlette &Sullivan 1961 and placed in the genera Cruciplacolithus
and Clausicoccus (Prins, 1979; Romein, 1979). The holotype of cribellum has narrower shields and a strongly perforate plate and is probably closely allied to, or a juniorsynonym of, Clausicoccus fenestratus. Differentiation: Distinguised from other Clausicoccus by larger
size, relatively wider shield and bright but indistinctly

36

Bown, Newsam

perforate central area plate. Dimensions: Holotype L= 12.7µm (Paratype L = 10.6µm). Holotype: Pl. 4, figs
42–43. Paratype: Pl. 4, figs 40–41. Type locality: IODP
Hole U1407A, NW Atlantic Ocean. Type level: Middle
Eocene, Sample U1407A-10-2, 100cm (Subzone NP14a).
Occurrence: Subzone NP14a; IODP Site U1407. Difficult to determine its range from published records, which
often combine C. norrisii and C. fenestratus. Reported as
NP11–17 by Shamrock & Watkins (2012) for C. fenestrata-like specimens >10µm in length.
Clausicoccus subdistichus (Roth & Hay in Hay et al.,1967) Prins, 1979
Pl. 4, figs 33–34; Pl. 14, figs 11–12
Clausicoccus vanheckiae (Perch-Nielsen, 1986) deKaenel & Villa, 1996
Pl. 4, figs 38–39
Hughesius tasmaniae (Edwards & Perch-Nielsen,1975) de Kaenel & Villa, 1996
Pl. 4, figs 31–32
Family CALCIDISCACEAE Young & Bown, 1997
Remarks: We follow the classification of Young & Bown
(2014) by placing the majority of Paleogene calcidiscids
with closed central-areas in Calcidiscus and those with
open central-areas in Umbilicosphaera. The excellent
preservation of the Exp. 342 material reveals the presenceof many of the calcidiscid species described from the Tanzania lagerstätte.
Calcidiscus bicircus Bown, 2005
Pl. 4, figs 46–47
Calcidiscus gerrardii Bown, 2005
Pl. 4, figs 52–53
Calcidiscus henrikseniae Bown, 2005
Pl. 4, figs 54–57
Calcidiscus scullyae sp. nov.
Pl. 4, figs 48–51
Derivation of name: Named after Caitlin Scully (Scripps
Institution of Oceanography, USA), Exp. 342 Education
Officer. Diagnosis: Medium-sized, circular-subcircular
placoliths with a non-birefringent distal shield, a narrow, bright tube-cycle and narrow central-area spanned
by low-birefringence crossbars. Differentiation: Similar to C. bicircus but with narrow central area spannedby crossbars (see also Bown, 2005, Pl. 9, figs 21–22).
Calcidiscus parvicrucis Bown, 2005 is elliptical, has amore distinct tube cycle and a younger range (Lower
Eocene). Dimensions: Holotype L = 6.3µm (Paratype
L = 6.0µm). Holotype: Pl. 4, figs 48–49. Paratype:Pl. 4, figs 50–51. Type locality: IODP Hole U1407A,
NW Atlantic Ocean. Type level: Middle Eocene, Sample U1407B-8-CC (Subzone NP14b). Occurrence:
Subzone NP14b; IODP Site U1407 (also Tanzania TDP
Site U2; Bown, 2005).

Umbilicosphaera bramlettei (Hay & Towe, 1962)
Bown et al., 2007
Pl. 5, figs 7–9; Pl. 14, figs 7–8
Remarks: Umbilicosphaera bramlettei varies significantly in size through the Eocene and here we distinguisha large variant, with diameter typically greater than 7.5µm.
These large coccoliths are very similar to the image named
as Coronocyclus prionion by Shamrock and Watkins(2012), defined therein as being >7.5µm, but the holotype
of prionion has a strongly serrated outline and appears to
be a Coronocyclus coccolith.
Umbilicosphaera detecta (de Kaenel & Villa, 1996)
Young & Bown, 2014
Pl. 5, fig. 10
Umbilicosphaera elliptica (Shamrock & Watkins,2012) comb. nov.
Pl. 5, figs 1–3
Basionym: Calcidiscus ellipticus Shamrock & Watkins,2012, p. 25, pl. 1, fig. 13. Stratigraphy, 9: 1–54. Remarks:
Following Young and Bown (2014), we place this calcidiscid with open, central area within Umbilicosphaera. Occurrence: Reported as NP14a-21 in Shamrock and Watkins(2012), we only found unequivocal forms in Subzone NP14b.
This morphology is also similar to that seen in Bramletteius
serraculoides and Umbilicosphaera detecta.
Umbilicosphaera protoannula (Gartner, 1971) Young &Bown, 2014
Pl. 5, figs 4–6
Placolith coccoliths Incertae Sedis
Birkelundia arenosa Perch-Nielsen, 1971
Pl. 5, figs 11–14
Ellipsolithus lajollaensis Bukry & Percival, 1971
Pl. 5, figs 16–17
Markalius latus Shamrock & Watkins, 2012
Pl. 5, fig. 27
Remarks: Large Markalius (5.5–9.1µm) with a wide birefringent cycle occupying >33 % of the coccolith diameter(Shamrock and Watkins, 2012). Occurrence: NP9/10-14b
according to Shamrock and Watkins (2012).
Pedinocyclus annulus Shamrock & Watkins, 2012
Pl. 5, figs 20–25
Remarks: Medium to large elliptical placolith with a brightinner cycle and open central area. Occurrence: Subzone
NP14b-21 according to Shamrock & Watkins (2012).
Tetralithoides symeonidesii Theodoridis, 1984
Pl. 5, figs 18–19
Coccolith indet. cf. Hayella sp.
Pl. 5, figs 27–28

Calcareous nannofossils from the Eocene North Alantic Ocean…

Description: High, circular coccolith with relatively
bright XPL image and strongly inclined elements. Occurrence: Zone NP13, Site U1407.
Coccolith indet. cf. Scyphosphaera sp.
Pl. 5, figs 29–31
Description: Very high nannofossil with gently tapering,
narrow walls, seen in side view. Occurrence: Zone NP13,
Site U1407.
Coccolith indet. cf. Staurolithites sp.
Pl. 5, figs 32–33
Description: Small coccolith with high, narrow rim andaxial cross. Occurrence: Zone NP22, Site U1411.
10.2 Murolith coccoliths
10.2.1 Mesozoic murolith lineages
Order EIFFELLITHALES Rood et al., 1971
Family CHIASTOZYGACEAE Rood et al., 1973
Jakubowskia leoniae Varol, 1989
Pl. 5, figs 34–35
Neocrepidolithus grandiculus Bown, 2005
Pl. 5, figs 36–37
Family GONIOLITHACEAE Deflandre, 1957
Goniolithus fluckigeri Deflandre, 1957
Pl. 5, figs 38–39
10.2.2 Cenozoic muroliths
Order ZYGODISCALES Young & Bown, 1997
Family HELICOSPHAERACEAE Black, 1971
Helicosphaera bramlettei (Müller, 1970) Jafar &Martini, 1975
Pl. 5, fig. 40; Pl. 14, fig. 16
Helicosphaera clarissima Bown, 2005
Pl. 5, fig. 41
Helicosphaera compacta Bramlette & Wilcoxon, 1967
Pl. 5, fig. 42; Pl. 14, fig. 19
Helicosphaera lophota (Bramlette & Sullivan, 1961)
Locker, 1973
Pl. 5, fig. 43
Helicosphaera papillata Bukry & Bramlette, 1969
Pl. 5, fig. 44; Pl. 14, figs 17–18
Helicosphaera prolixa sp. nov.
Pl. 5, figs 47–51
Derivation of name: From prolixus, meaning ‘wide’,referring to the broad overall shape of this species. Diagnosis: Large, broadly elliptical Helicosphaera with narrow
central area spanned by an oblique, disjunct, broad bar.
The coccolith is relatively birefringent across the width of
the rim. Differentiation: Distinguised from other Helicosphaera by the broadly elliptical outline and high birefringence image in XPL. Dimensions: Holotype L = 10.9µm(Paratype L = 12.2µm). Holotype: Pl. 5, figs 47–48.

37

Paratype: Pl. 5, figs 49–50. Type locality: IODP Hole
U1410A, NW Atlantic Ocean. Type level: Middle Eocene,
Sample U1410A-14H-7, 82cm (Zone NP16). Occurrence: Zone NP16; IODP Site U1410.
Helicosphaera reticulata Bramlette & Wilcoxon, 1967
Pl. 5, fig. 45
Helicosphaera seminulum Bramlette & Sullivan, 1961
Pl. 14, fig. 15
Helicosphaera wilcoxonii (Gartner, 1971) Jafar &Martini, 1975
Pl. 5, fig. 46; Pl. 14, fig. 14
Family PONTOSPHAERACEAE Lemmermann, 1908
Pontosphaera alta Roth, 1970
Pl. 6, fig. 11
Pontosphaera brinkhuisii sp. nov.
Pl. 6, fig. 1–4
Derivation of name: Named after Dan Brinkhuis (Science Media NL, The Netherlands), Exp. 342 videographer and film maker. Diagnosis: Very large, elliptical
pontosphaerid with broad, high rim and narrow, apparently vacant central area. Remarks: Possibly the taxon
that Bralower & Mutterlose (1995) call Reticulofenestra “grandis” with a reported range of Zones NP15–16.
Differentiation: Distinguised from other Pontosphaera
by larger size, thick rim cycles and vacant central area.
Dimensions: Holotype L = 21.2µm (Paratype L =17.1µm).
Holotype: Pl. 6, figs 1–2. Paratype: Pl. 6, figs 34. Type
locality: IODP Hole U1409A, NW Atlantic Ocean. Typelevel: Middle Eocene, Sample U1409A-7H-CC (Subzone
NP15b). Occurrence: Subzone NP15b-16; IODP Sites
U1408, U1409
Pontosphaera clinosulcata Bown, 2005
Pl. 6, fig. 12
Pontosphaera enormis (Locker, 1967) Perch-Nielsen,
1984
Pl. 6, fig. 13
Pontosphaera exilis (Bramlette & Sullivan, 1961)
Romein, 1979
Pl. 6, fig. 14
Pontosphaera formosa (Bukry & Bramlette, 1968)
Romein, 1979
Pl. 6, figs 23–24
Pontosphaera hollisii sp. nov.
Pl. 6, figs 9–10
Derivation of name: Named after Chris Hollis (GNS Science, New Zealand), Exp. 342 shipboard scientist, micropalaeontologist and palaeoceanographer. Diagnosis: Verylarge, broadly elliptical pontosphaerid with broad, low rim
and narrow to closed central area. The rim is pale grey incross-polarised light. Differentiation: Distinguised fromother Pontosphaera by larger size, broad rim cycle and38

Bown, Newsam

low birefringence in cross-polarised light. Dimensions:
Holotype L = 18.1µm (Paratype L = 18.3µm). Holotype:
Pl. 6, fig. 9. Paratype: Pl. 6, fig. 10. Type locality: IODP
Hole U1409A, NW Atlantic Ocean. Type level: Middle Eocene, Sample U1409A-7H-CC (Subzone NP15b).
Occurrence: Subzone NP15b-c; IODP Site U1409.
Pontosphaera latoculata (Bukry & Percival, 1971)
Perch-Nielsen, 1984
Pl. 6, figs 15–16
Pontosphaera multipora (Kamptner, 1948 ex
Deflandre, 1954) Roth, 1970
Pl. 6, fig. 25
Pontosphaera obliquipons (Deflandre in Deflandre &Fert 1954) Romein 1979
Pl. 6, fig. 22
Pontosphaera pulchra (Deflandre in Deflandre & Fert,
1954) Romein, 1979
Pl. 6, fig. 26; Pl. 14, fig. 20
Pontosphaera romansii sp. nov.
Pl. 6, figs 17–21
Derivation of name: Named after Brian Romans (Virginia
Polytechnic Institute and State University, USA), Exp. 342
shipboard scientist, sedimentologist and palaeoceanographer. Diagnosis: Large, narrowly elliptical, lens-shaped
pontosphaerid with high rim and apparently vacant central
area. Differentiation: Distinguised from other pontosphaerids by the high, lens-shaped rim. Dimensions: Holotype L = 10.5µm (Paratype L = 11.9µm). Holotype: Pl. 6,
figs 17–20. Paratype: Pl. 6, fig. 21. Type locality: IODP
Hole U1409A, NW Atlantic Ocean. Type level: Middle Eocene, Sample U1409A-8H-CC (Subzone NP15b).
Occurrence: Subzone NP15b; IODP Site U1409.
Pontosphaera wilsonii sp. nov.
Pl. 6, fig. 5–8
Derivation of name: Named after Paul Wilson (Universityof Southampton, UK), Exp. 342 co-chief scientist and palaeoceanographer. Diagnosis: Elliptical pontosphaerid withcentral area plate crossed by prominent oblique ridges thatare bright in cross-polarised light. Differentiation: Distinguised from other Pontosphaera by the distinctive oblique
ridges than run across the coccolith. Dimensions: Holotype
L = 6.7µm (Paratype L = 7.4µm). Holotype: Pl. 6, fig. 6.
Paratype: Pl. 6, fig. 8. Type locality: IODP Hole U1410A,NW Atlantic Ocean. Type level: Middle Eocene, Sample
U1410A-17X-1, 75cm (Subzone NP15c). Occurrence:
Subzone NP15b-16; IODP Sites U1408, U1409, U1410.
Pontosphaera zigzag (Roth & Hay, 1967 in Hay et al.
1967) comb. nov.
Pl. 6, figs 27–29
Basionym: Transveropontis zigzag Roth & Hay, 1967 in
Hay et al. 1967, p. 450, Plate 7, fig. 4. Transactions of
the Gulf Coast Association of Geological Societies, 17,

428–480. Description: Small Pontosphaera with obliquebar usually with a distinct kink and perforate. Remarks:
Reported as ranging from the middle Eocene (e.g. SelfTrail, 2011) to Oligocene but is often most conspicuous
across the Eocene/Oligocene transition. Occurrence:
Zone NP15c-22; IODP Site U1498, 1410 and 1411.
NP14–16 (Self-Trail, 2011).
Scyphosphaera apsteinii Lohmann, 1902
Pl. 6, figs 38–40; Pl. 12, fig. 9; Pl. 14, fig. 21
Scyphosphaera columella Stradner, 1969
Pl. 6, fig. 36
Scyphosphaera expansa Bukry & Percival, 1971
Pl. 6, fig. 37; Pl. 14, fig. 22
Scyphosphaera interstincta sp. nov.
Pl. 6, figs 30–35
Derivation of name: From interstinctus, meaning ‘spotted’, referring to the appearance of the wall of this species.
Diagnosis: Elongate-barrel shaped Scyphosphaera with
distinct wall ornament of large pits or pores. The coccolith wall tapers gently both proximally and distally, andthe inner cycle thickens at the distal opening. Differentiation: Distinguised from other Scyphosphaera by the wall
ornament and inner cycle thickening at the distal opening.
Dimensions: Holotype L/W = 7.7µm; H = 14.3µm (Paratype L/W = 8.3µm; H = 14.3µm). Holotype L/W = 6.1µm;
H = 11.3µm Holotype: Pl. 6, figs 30–31. Paratype:
Pl. 6, figs 34–35. Type locality: IODP Hole U1408A,
NW Atlantic Ocean. Type level: Upper Eocene, Sample
U1408A-14H-5, 63cm (Zone NP16). Occurrence: Zone
NP15b-16; IODP Sites U1408 and 1409.
Family ZYGODISCAEAE Hay & Mohler, 1967
Lophodolithus mochlophorus Deflandre in Deflandre &Fert, 1954
Pl. 8, figs 11–14
Lophodolithus rotundus Bukry & Percival 1971
Pl. 8, figs 15–16
Neococcolithes-Nannotetrina Group
Plate 7; Figure 3
Description: Distinctive and unusual coccoliths/nannoliths ranging from simple muroliths (Isthmolithus, Neococcolithes), through modified-coccoliths with very high andragged rims (Chiphragmalithus), to cruciform and stellate
nannoliths, with relict or lost rims (Nannotetrina). All
share a common crystallographic orientation with crystal
units in near-extinction in cross-polarized light, and mostare characterised by the presence of diagonally-orientatedcrossbars. In Chiphragmolithus the rim is elevated andoften irregular in outline due to lateral outgrowths. In
Nannotetrina the coccolith rim is lost or relict, and themodified crossbars form the majority of the lith. Throughout the group the coccolith rims or nannoliths are highand often seen in side view (Pl. 7, figs 45–50). IncludedCalcareous nannofossils from the Eocene North Alantic Ocean…

genera: Chiphragmalithus, Isthmolithus, Nannotetrina,
Neococcolithes. Occurrence: Lower Paleocene-Lower
Oligocene (Zones NP5?-NP22).
Genus Chiphragmalithus Bramlette & Sullivan, 1961
Chiphragmalithus acanthodes Bramlette & Sullivan,
1961
Pl. 7, figs 4–12
Description: Elliptical, high rim with lateral projections and central area spanned by diagonal crossbars.
The crossbars are high and extend across the rim to thecoccolith edge. Remarks: Occurs with a number ofother unusual coccoliths (e.g. N. plana, N. ruda) close
to the first appearance of the Nannotetrina genus (seeSection 6). Occurrence: Zone NP14a-b; IODP Sites
U1408 and U1409.
Chiphragmalithus calathus Bramlette & Sullivan, 1961
Pl. 7, figs 13–15
Remarks: Circular, subcircular or slightly quadrate withsimple, high rim and diagonal crossbars. Occurrence:
Zone NP14; IODP Sites U1408 and U1409.
Genus Isthmolithus Deflandre in Deflandre & Fert,
1954
Isthmolithus recurvus Deflandre in Deflandre & Fert,
1954
Figure 3
Genus Nannotetrina Achuthan & Stradner, 1969
Nannotetrina alata (Martini, 1960) Haq & Lohmann,
1976
Pl. 12, fig. 11
Nannotetrina cristata (Martini, 1958) Perch-Nielsen,
1971
Pl. 7, figs 31–43, 50
Remarks: We use N. cristata here for an array of mediumto large-sized, three-dimensional nannoliths that arebroadly cross-shaped with arms that widen towards theirends and with inter-arm fill. They are frequently seen inside view, where they resemble side views of Chiphragmolithus (Pl. 7, fig. 50). A small number of specimens
observed in Subzone NP14b retain structures that appear
to resemble small, square-shaped coccolith rims and central area bars (Pl. 7, figs 37–43).
Nannotetrina fulgens (Stradner in Martini & Stradner,
1960) Achuthan & Stradner, 1969
Pl. 12, fig. 12
Nannotetrina pappii (Stradner, 1959) Perch-Nielsen,
1971
Figure 3
Nannotetrina plana sp. nov.
Pl. 7, figs 21–30

39

Derivation of name: From planus, meaning ‘flat’, referring to the relatively flat morphology of this species.
Diagnosis: Subcircular to broadly elliptical form comprising a low basal disc crossed by broad, raised crossbars. The constituent elements are in near-extinction in
XPL. Differentiation: Distinguished from Nannotetrina
cristata by rounder outline and relatively broader crossbars/ridges that do not thicken and twist at their ends.
Dimensions: Holotype L = 9.0µm (Paratype L = 9.3µm).
Holotype: Pl. 7, figs 21–23. Paratype: Pl. 7, figs 25–26.
Type locality: IODP Hole U1409A, NW Atlantic Ocean.
Type level: Middle Eocene, Sample U1409A-12H-4,
43cm (Subzone NP14b). Occurrence: Subzone NP14b;
Sites U1408 and U1409.
Nannotetrina ruda sp. nov.
Pl. 7, figs 16–20
Derivation of name: From ruda, meaning ‘rough lump’,referring to the coarse and blocky appearance of this species. Diagnosis: Subcircular to broadly elliptical form
comprising a rim and high, broad and blocky crossbars.
The constituent elements are in near-extinction in XPL.
Differentiation: Most similar to Nannotetrina plana sp.
nov. but blockier in overall form and the crossbars arebroader and higher. Dimensions: Holotype L = 11.2µm(Paratype L = 9.8µm). Holotype: Pl. 7, fig. 17. Paratype: Pl. 7, fig. 18. Type locality: IODP Hole U1409A,
NW Atlantic Ocean. Type level: Middle Eocene, Sample
U1409A-12H-4, 43cm (Subzone NP14b). Occurrence:
Zone NP14b; IODP Site U1409.
Nannotetrina spinosa (Stradner in Martini & Stradner,
1960) Bukry, 1973
Pl. 7, fig. 44
Genus Neococcolithes Sujkowski, 1931
Neococcolithes dubius (Deflandre in Deflandre & Fert,
1954) Black, 1967
Pl. 7, fig. 1; Pl. 14, fig. 23
Neococcolithes protenus (Bramlette & Sullivan, 1961)
Black, 1967
Pl. 7, figs 2–3, 45
Remarks: Elliptical, simple rim with diagonal crossbars.
Neococcolithes purus sp. nov.
Pl. 8, figs 8–10
Derivation of name: From purus, meaning ‘plain’, referring to the apparently vacant central area of this species.
Diagnosis: Narrowly-elliptical murolith coccolith with anarrow, low birefringence, unicyclic rim image and relatively wide, apparently vacant, central area. Remarks: To
date, its distribution is the same as that of Neococcolithes
radiatus sp. nov. Differentiation: Distinguished fromother species of Neococcolithes by the vacant central area.
Similar in overall form to Jakubowskia leoniae Varol,

40

Bown, Newsam

1989 but it is smaller, has a narrower, low birefringence
rim and a different stratigraphic range. Dimensions: Holotype L = 6.8µm (Paratype L = 5.7µm). Holotype: Pl. 8,
figs 8–9. Paratype: Pl. 8, fig. 10. Type locality: IODP
Hole U1410A, NW Atlantic Ocean. Type level: Middle
Eocene, Sample U1410A-7H-CC (Zone NP17). Occurrence: Zone NP17; IODP Sites U1408, U1410.
Neococcolithes radiatus sp. nov.
Pl. 8, figs 1–7
Derivation of name: From radiatus, meaning ‘with rays’,referring to the grill in the central area of this species. Diagnosis: Narrowly-elliptical murolith coccolith with a lowbirefringence, unicyclic rim image and central area withnumerous (around 18–22) radiating bars. Description: The
rim shows relatively low birefringence in XPL as do thecentral area bars. Some specimens have outlines approaching rhomboidal. Remarks: The rhomboidal outline andstratigraphic position close to the extinction of Neococcolithes dubius and first appearance of Isthmolithus recurvus
suggest that this may be a transitional species between thetwo genera. Differentiation: Distinguished from most otherspecies of Neococcolithes, which have diagonal crossbars,
by the more numerous central area bars. Dimensions: Holotype L = 7.6µm (Paratype L = 6.4µm). Holotype: Pl. 8, figs
1–4. Paratype: Pl. 8, figs 5–7. Type locality: IODP Hole
U1410A, NW Atlantic Ocean. Type level: Middle Eocene,
Sample U1410A-7H-CC (Zone NP17). Occurrence: Zone
NP17; IODP Site U1410.
Family RHABDOSPHAERACEAE Haeckel, 1894
Genus Blackites Hay & Towe, 1962
Blackites bases
Pl. 8, figs 17–39
Remarks: In well preserved material Blackites bases canbe common components of nannofossil assemblages,
albeit inconspicuous because of their low birefringence
images in XPL. They represent both the disarticulatedbases of spinose forms, together with non-spinose coccoliths, such as B. amplus and B. furvus. Small Blackites
bases (Pl. 8, figs 22–23) are common through the middle
to late Eocene of the Exp. 342 sites and are most likely
the disarticulated bases of the common species B. spinosus
and B. tenuis.
Blackites amplus Roth & Hay, 1967
Pl. 8, figs 17–21
Blackites creber (Deflandre in Deflandre & Fert, 1954)
Sherwood, 1974
Pl. 9, fig. 9Blackites deflandrei (Perch-Nielsen 1968) Bown, 2005
var. 1Pl. 8, figs 42, 43, 47; Pl. 15, figs 1–2
Remarks: Blackites with broad coccolith base and broad,thin-walled, variably tall, dome-like to bullet-shaped

spine. The spine is ornamented and parallel-sided in its
lower part before tapering to a point. In SEM the ornamentation is revealed to be perforations/windows. The
species was originally defined and illustrated as having
variable spine height but the complete type specimens
have a height less than the coccolith rim width. Here we
distinguish two informal varieties based on spine height:
variety 1 with height<coccolith rim width and variety 2
with height> coccolith rim width.
Blackites deflandrei (Perch-Nielsen 1968) Bown, 2005
var. 2
Pl. 8, figs 48–52
Remarks: Like B. deflandrei var. 1 but with with spine
height>coccolith rim width. Occurrence: Zone NP1619/20; IODP Site U1410, U1411.
Blackites dupuisii (Steurbaut, 1990) Bown, 2005
Pl. 8, figs 53–55
Blackites friedrichii sp. nov.
Pl. 8, figs 29–39
Derivation of name: Named after Oliver Friedrich (University of Heidelberg, Germany), Exp. 342 shipboard
scientist, micropalaeontologist and palaeoceanographer.
Diagnosis: Blackites with broad circular base and broad,low, thin-walled, globular spine with distinct image in
XPL having a crenulate edge and strong extinction cross.
Typically seen in plan view. Differentiation: Distinguisedfrom most Blackites bases by it large diameter and from
B. amplus by its distinctive, low, globular spine. Dimensions: Holotype L = 5.4µm (Paratype L = 4.5µm). Holotype: Pl. 7, fig. 33. Paratype: Pl. 7, fig. 30. Type locality:
IODP Hole U1408C, NW Atlantic Ocean. Type level:
Middle Eocene, Sample U1408C-10X-3, 63cm (Zone
NP16). Occurrence: Zones NP16–17; IODP Site U1408,
U1409, U1410.
Blackites furvus Bown & Dunkley Jones, 2006
Pl. 8, figs 24–28
Blackites gladius (Locker, 1967) Varol, 1989
Pl. 9, figs 5–6; Pl. 15, fig. 3Blackites globosus Bown, 2005
Pl. 8, figs 56–58
Blackites cf. B. herculesii (Stradner, 1969) Bybell &Self-Trail, 1997
Pl. 9, figs 35–39
Remarks: Tall, narrow, club-like, disarticulated Blackites spines that narrow towards both ends and which havea dark image in XPL. Occurrence: Zones 15b-17; Site
U1409.
Blackites inflatus (Bramlette & Sullivan, 1961)
Kapellos & Schaub, 1973
Pl. 9, figs 10, 30

Calcareous nannofossils from the Eocene North Alantic Ocean…

Blackites inversus (Bukry & Bramlette, 1969) comb. nov.
Pl. 9, fig. 26
Basionym: Triquetrorhabdulus inversus Bukry & Bramlette, 1969, Some new and stratigraphically useful calcareous nannofossils of the Cenozoic. Tulane Studies inGeology, 7: p.142, pl. 1, figs 9–14. Description: Very longspinose forms that taper towards each end and which have
undulating outline and narrow axial canal. In XPL they aredark at 0° and bright at 45°. Remarks: Previously placedin Triquetrorhabdulus by Bukry & Bramlette (1969) and
Pseudotriquetrorhabdulus by Wise (in Wise & Constans,1976), these spinose forms occur alongside other Blackites
spines with similar LM image and cystallographic orientation, and they most likely represents a Blackites species
that readily detaches from its coccolith base. It can occur
abundantly and has a relatively restricted stratigraphic
range in the middle Eocene (Zones NP14–15), with aparticular acme interval in Zone NP14 (Backman, 1986).
Occurrence: Zones NP14–15.
Blackites kilwaensis Bown, 2005
Pl. 9, fig. 12Blackites ornatus Bown & Dunkley Jones, 2006
Pl. 9, fig. 13
Blackites perlongus (Deflandre, 1952) Shafik, 1981
Pl. 9, figs 22–23
Blackites piriformis (Pavsic in Khan et al., 1975)
Aubry, 1999
Pl. 9, fig. 11
Blackites pseudomorionum (Locker 1967) Aubry 1999
Pl. 8, fig. 46
Blackites cf. B. pseudomorionum (Locker 1967) Aubry1999
Pl. 8, figs 44–45
Blackites rotundus Bown, 2005
Pl. 9, figs 7–8
Blackites sextonii sp. nov.
Pl. 9, figs 1–4
Derivation of name: Named after Phil Sexton (Open University, UK), Exp. 342 shipboard scientist, micropalaeontologist and palaeoceanographer. Diagnosis: Blackites
with broad base, and very tall, broad, thin-walled spine.
The broad spine is near-parallel sided or very gently
tapering for most of its length before tapering sharply toa point. Differentiation: Distinguised from other Blackites by its broad, very tall spine. Dimensions: Holotype
max coccolith base W = 5.9µm; spine L = 13.1µm, spine
W = 2.3µm (Paratype spine L = 12.7µm). Holotype: Pl. 8,
fig. 1. Paratype: Pl. 8, figs 3, 4. Type locality: IODP Hole
U1408C, NW Atlantic Ocean. Type level: Upper Eocene,
Sample U1408C-7H-4, 93cm (Zone NP16). Occurrence:
Zone NP16; IODP Site U1408.
Blackites subtilis sp. nov.
Pl. 9, figs 27–29

41

Derivation of name: From subtilis, meaning ‘slender’,referring to the very narrow form of this spine. Diagnosis:
Very long, slender spine that is near-parallel-sided with anarrow axial canal. In XPL, the spine is dark when parallelwith the polarising directions and bright at 45°. It is typically seen with no basal coccolith. Differentiation: Most
likely a spine of the genus Blackites, but distinguishedfrom other narrow-spined species, such as B. perlongus
and B. tenuis, by its length, very narrow axial canal andlack of taper. Dimensions: Holotype spine L = 22.4µm,
spine W = 1.2µm (Paratype minimum L = 16.1µm, spine
W = 1.2µm). Holotype: Pl. 9, fig. 27. Paratype: Pl. 9,
fig. 28. Type locality: IODP Hole U1407A, NW Atlantic
Ocean. Type level: Upper Eocene, Sample U1407A-9H-6,
57cm (Subzone NP14b). Occurrence: Subzone NP14bZone NP16; IODP Sites U1407, U1408 and U1409.
Blackites spinosus (Deflandre & Fert, 1954) Hay &Towe, 1962
Pl. 9, figs 31–32; Pl. 15, fig. 4Blackites cf. B. spinosus (Deflandre & Fert, 1954) Hay& Towe, 1962
Pl. 9, fig. 21
Blackites stilus Bown, 2005
Pl. 9, figs 24–25
Blackites tenuis (Bramlette & Sullivan 1961)
Sherwood, 1974
Pl. 9, figs 33–34; Pl. 15, fig. 5Blackites tortilis Bown & Dunkley Jones, 2006
Pl. 9, figs 16–20; Pl. 15, fig. 6Blackites virgatus Bown, 2005
Pl. 9, figs 14–15
Rhabdosphaera gracilenta (Bown & Dunkley Jones,
2006) Dunkley Jones et al., 2009
Pl. 9, figs 40–44
Remarks: Transferred from Blackites to Rhabdosphaera
by Dunkley Jones et al. (2009) but spelt gracilentus.
Orthography corrected here.
Rhabdosphaera vitrea (Deflandre in Deflandre & Fert
1954) Bramlette & Sullivan, 1961
Pl. 9, figs 45–48
Order SYRACOSPHAERALES Hay, 1977 emend.
Young et al., 2003
Family CALCIOSOLENIACEAE Kamptner, 1927
Calciosolenia alternans Bown & Dunkley Jones, 2006
Pl. 9, fig. 49
Family SYRACOSPHAERACEAE Lemmermann,
1908
Syracosphaera octiforma sp. nov.
Pl. 9, figs 51–54
Derivation of name: From octi, meaning ‘eight’, and‘forma’ meaning form, referring to the distinctive outline

42

Bown, Newsamof this species. Diagnosis: Narrow rimmed coccolith with
figure-of-eight outline (indentations on each side). In XPL
the rim is relatively bright and there may be a spine in
the central area, which is otherwise unclear. Remarks: We
tentatively assign this species to Syracosphaera based on
the rim image in XPL. Differentiation: Distinguised frommost other coccoliths by its distinctive outline. Dimensions: Holotype L = 5.5µm (Paratype L = 5.2µm). Holotype: Pl. 9, figs 53–54. Paratype: Pl. 9, figs 51–52. Type
locality: IODP Hole U1408A, NW Atlantic Ocean. Typelevel: Upper Eocene, Sample U1408A-4H-CC (Zone
NP17). Occurrence: Zone NP16–17; IODP Sites U1408,
U1410.
Syracosphaera tanzanensis Bown, 2005
Pl. 8, fig. 50
Murolith coccoliths Incertae Sedis
Pocillithus spinulifer Dunkley Jones et al., 2009
Pl. 15, figs 7–8
10.3 Holococcoliths
Family CALYPTROSPHAERACEAE Boudreaux &Hay, 1967
Daktylethra punctulata Gartner in Gartner & Bukry,
1969
Pl. 10, figs 4–6
Daktylethra unitatis Bown & Dunkley Jones, 2006
Pl. 10, figs 1–3; Pl. 15, fig. 9
Holodiscolithus agniniae sp. nov.
Pl. 10, figs 14–21
Derivation of name: Named after Claudia Agnini (Univeristy of Padua, Italy), Exp. 342 shipboard scientist, nannopalaeontologist and biostratigrapher. Remarks: Flat,
elliptical holococcolith formed from six crystallographic
blocks divided by near-radial sutures. Differentiation:
Similar to Cretaceous coccoliths of the genus Calculites,
but this species is distinguished by being flat and having
six similarly-sized crystallographic blocks. Dimensions:
Holotype L = 4.9µm (Paratype L = 4.8µm). Holotype:Pl. 9, figs 17–19. Paratype: Pl. 9, figs 14–16. Type locality: IODP Hole U1407A, NW Atlantic Ocean. Type level:
Middle Eocene, Sample U1407A-9H-6, 58cm (Subzone
NP14b). Occurrence: Subzone NP14b; IODP Site U1407.
Holodiscolithus lippertii sp. nov.
Pl. 10, figs 33–38
Derivation of name: Named after Peter Lippert (University of Utah, USA), Exp. 342 shipboard scientist, palaeomagnetist and palaeoceanographer. Diagnosis: Small,
elliptical, moderately-birefringent holococcolith crossedby roughly diagonal extinction lines in XPL delineating
four blocks, which are birefringent at 0° and dark at 45°.
There are around 8–10 perforations across the blocks
and raised axial ridges are visible in phase contrast.

Differentiation: The perforations are smaller than Holodiscolithus solidus and less numerous than Holodiscolithus
macroporus. Dimensions: Holotype L = 3.2µm (Paratype
L = 3.4µm). Holotype: Pl. 10, figs 36–38. Paratype:
Pl. 10, figs 33–35. Type locality: IODP Hole U1411B,
NW Atlantic Ocean. Type level: Eocene/Oligocene transition, Sample U1411C-8H-6, 60cm (Zone NP21). Occurrence: Zone NP21; IODP Site U1411.
Holodiscolithus liuii sp. nov.
Pl. 10, figs 22–26
Derivation of name: Named after Zhonghui Liu (Department of Earth Sciences, University of Hong Kong), Exp.
342 shipboard scientist, geochemist and palaeoceanographer. Diagnosis: Small, elliptical holococcolith withnarrow rim and broad bar that almost fills the central
area; the bar is dark at 0° and birefringent at 45°. Differentiation: Similar to H. serus but is more regular in outline and shows no perforations. Dimensions: Holotype
L = 3.9µm (Paratype L = 3.9µm). Holotype: Pl. 10, figs
24–26. Paratype: Pl. 10, fig. 22. Type locality: IODP
Hole U1407A, NW Atlantic Ocean. Type level: Middle
Eocene, Sample U1407A-9H-6, 57cm (Subzone NP14b).
Occurrence: Subzone NP14b; IODP Site U1407.
Holodiscolithus solidus (Deflandre in Deflandre &Fert, 1954) Roth, 1970
Pl. 10, figs 9–13; Pl. 15, fig. 10
Holodiscolithus whitesideae sp. nov.
Pl. 10, figs 27–30
Derivation of name: Named after Jessica Whiteside(University of Southampton, UK), Exp. 342 shipboard
scientist, geochemist and palaeoceanographer. Diagnosis: Small holococcolith seen in side view, with steepsided base and short, narrow spine. All parts of theholococcolith show similar crystallographic orientationand it is moderately birefringent at 45°, and dark at 0°.
A median septum appears to be present. Differentiation: Dimensions: Holotype L = 3.1µm, H = 3.3µm(Paratype L = 2.8µm, H = 2.9µm). Holotype: Pl. 10,
figs 27–28. Paratype: Pl. 10, figs 29–30. Type locality:
IODP Hole U1408C, NW Atlantic Ocean. Type level:
Middle Eocene, Sample U1408C-10H-3, 63cm (Zone
NP16). Occurrence: Zone NP16; IODP Site U1408.
Lanternithus minutus Stradner, 1962
Pl. 10, figs 7–8; Pl. 15, fig. 11
Semihololithus pseudobiskayae sp. nov.
Pl. 10, figs 39–44
Derivation of name: From the Greek word pseudes,
meaning ‘false’, and referring to its similarity to the older,
Paleocene species Semihololithus biskayae. Diagnosis:
Large, blocky coccolith seen in side view, with steepwalled rim and domed upper surface. Differentiation:

Calcareous nannofossils from the Eocene North Alantic Ocean…

Similar in overall shape to Semihololithus biskayae but
has a more irregular appearance, lower birefringence
image and blockier upper cover. Dimensions: Holotype
L = 6.6µm, H = 6.5µm (Paratype L = 6.6µm, H = 6.8µm).
Holotype: Pl. 10, fig. 43–44. Paratype: Pl. 10, figs 41–42.
Type locality: IODP Hole U1407A, NW Atlantic Ocean.
Type level: Middle Eocene, Sample U1407A-9H-6, 57cm
(Subzone NP14b). Occurrence: Subzone NP14b; IODP
Sites U1407 and U1408.
Zygrhablithus bijugatus bijugatus (Deflandre in
Deflandre & Fert, 1954) Deflandre, 1959
Pl. 10, figs 45–50; Pl. 15, fig. 12
Holococcolith sp. indet.
Pl. 10, figs 31–32
Remarks: Small, elliptical holococcolith with transverse
bar, displaying a low birefringence image in XPL andhigh relief in PC. Occurrence: Middle Eocene, Subzone
NP14b; Site U1407.
10.4 Extinct nannoliths
Order DISCOASTERALES Hay, 1977 emend. Bown,
2010
Family DISCOASTERACEAE Tan, 1927
Discoaster barbadiensis Tan, 1927
Pl. 15, fig. 14
Discoaster distinctus Martini, 1958
Pl. 15, fig. 17
Discoaster martinii Stradner, 1959
Pl. 12, fig. 10
Discoaster nodifer (Bramlette & Riedel, 1954) Bukry,
1973
Pl. 15, figs 15, 18
Discoaster saipanensis Bramlette & Riedel, 1954
Pl. 15, fig. 13
Family SPHENOLITHACEAE Deflandre, 1952
Sphenolithus furcatolithoides Subgroup
Pl. 11, figs 1–29
Remarks: Included within the S. radians group by Bown
& Dunkley Jones (2012), these species are characterised bytwo (rarely more) bifurcating apical spines, bright at 0° anddark at 45°, extending from the upper quadrants. Species
differentiation is based on the height and angle of spine
bifurcation and size of the basal quadrants. In moderate topoor preservation the upper portion of these tall spines isusually lost, but when well preserved, as seen herein, theentire lith may be preserved, highlighting the extreme spine
lengths (up to 25µm; Pl. 11, fig. 25) and variations in upper
spine morphology. Morphology within the group includes:
1. S. kempii – square base with three of four spines;
2. S. cf. S. perpendicularis – tapering base with narrow,high-angled lateral spines;
3. S. perpendicularis Shamrock, 2010 – square base with
two spines that diverge by around 90°;

43

4. S. furcatolithoides – spines diverge just above the baseand are near-parallel in the lower part;
5. S. cuniculus – forms with low basal quadrants (‘feet’)and ~90° bifurcations; and6. S. strigosus – duocrystalline spines that bifurcate
high-up on the spine.
In the slightly younger, and probably descendant, S. predistentus group, only the lower quadrants are clearly discernable in the basal column and the spines are bright at
45° and diverge in the uppermost part of the spine (e.g. S.
obtusus, S. runus, S. predistentus).
Sphenolithus cuniculus Bown, 2005
Pl. 11, figs 19–20, 25
Sphenolithus furcatolithoides Locker 1967
Pl. 11, figs 15–18, 21–22, 26
Description: Typified by two apical spines that extend
and diverge from the upper basal quadrants but that arenear-parallel in the lower, normally preserved, part. Whenpreservation is very good, the upper part of the spines arepreserved and may be near-parallel or diverge from thelong axis of the sphenolith by varying amounts. Variants
include small, gracile forms with near-parallel bifurcations that bend to form higher degree (>90°) bifurcations
high on the spine (Pl. 11, fig. 26), and forms with upper
spines that converge (Pl. 11, fig. 22). Specimens at thebase of the species range at Site U1410 appear most similar to S. radians (Pl. 11, figs 14–15).
Sphenolithus cf. S. kempii sensu Bown & Dunkley
Jones, 2012
Pl. 11, figs 4–6
Sphenolithus perpendicularis Shamrock, 2010
Pl. 11, figs 9–13
Description: Sphenolith with two apical spines thatdiverge by ~90° (45° to the sphenolith long axis) justabove the basal cycles. Restricted to Subzone NP15a
according to Shamrock (2010). Informally identified
as Sphenolithus “spinatus” by Bralower & Mutterlose(1995) and shown ranging from upper Subzone NP14b
to Subzone NP15b. The S. perpendicularis-like forms
seen in the Exp. 342 material have narrower spines
but this may be due to overgrowth in the type material.
Forms where the spines make a distinct angle with theupper basal quadrant are distinguished as Sphenolithus
cf. S. perpendicularis herein. Occurrence: Subzone
NP14b-15b. Sites U1407, U1408.
Sphenolithus cf. S. perpendicularis Shamrock, 2010
Pl. 11, figs 1–3
Description: Short, squat sphenoliths with a base formed
from broad, gently-tapering lower quadrants and smaller
upper quadrants. Two long, narrow, lateral spines emerge44

Bown, Newsam

from the upper quadrants making an angle of around 160°
(80° to the sphenolith long axis). Differentiation: The baseis most similar to S. moriformis or S. spiniger but this species is distinguised from these by long lateral spines. The
spines are most similar to S. furcatolithoides group sphenoliths, but are narrower and emerge from the base at a higher
angle. Occurrence: Subzone NP14b-15b. Site U1408.
Sphenolithus strigosus Bown & Dunkley Jones 2006
Pl. 11, figs 23, 27–29; Pl. 15, fig. 22
Sphenolithus predistentus GroupPl. 11, figs 30–43
Remarks: These species are characterised by a basewith two, low quadrants (or ‘feet’) and tapering duo- or
monocrystalline spines with terminal bifurcations that
may be very long. The spines are visible but dim at 0° andbrightest when at 45° to the polarizing directions.
Sphenolithus obtusus Bukry 1971
Pl. 11, figs 36–38, 40–41; Pl. 15, fig. 21
Sphenolithus predistentus Bramlette & Wilcoxon 1967
Pl. 11, figs 42–43
Sphenolithus runus Bown & Dunkley Jones 2006
Pl. 11, figs 30–35
Remarks: Similar to S. obtusus but the spine is dark at 0°
and does not appear duocrytalline at 45°.
Other sphenoliths
Sphenolithus moriformis (Brönnimann & Stradner,
1960) Bramlette & Wilcoxon, 1967
Pl. 15, fig. 19
Sphenolithus radians Deflandre in Grassé 1952
Pl. 15, fig. 16
Sphenolithus spiniger Bukry 1971
Pl. 15, fig. 20
Sphenolithus spines
Pl. 11, figs 24, 39, 44–45
Remarks: Several middle Eocene sphenoliths have verytall spines which, when well preserved, retain even longer,
usually bifurcating, terminal spine ends (e.g. S. cuniculus,
S. furcatolithoides, S. obtusus, S. strigosus). These spines
may reach up to 32µm in length, and in S. furcatolithoides
they take on a variety of different shapes, with up to two
inflection points. In a number of stratigraphic intervals
narrow spine-like liths are common and may represent
broken sphenolith spines. However, in some case theseliths have triradiate form, which do not appear to havebeen sourced from sphenoliths (Pl. 11, figs 39, 45).
Incertae Sedis Nannoliths
Leesella procera Bown & Dunkley Jones, 2006
Pl. 11, figs 46–48

Acknowledgements
Thanks to IODP Expedition 342 operational and technicalstaff and shipboard science party for facilitating such an
enjoyable and successful drilling expedition. This researchused samples provided by the Integrated Ocean Drilling
Program (IODP). Funding for this research was provided toPB (Expedition participation) and CN (PhD studentship) by
the Natural Environment Research Council (NERC).
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Plate 1

Calcareous nannofossils from the Eocene North Alantic Ocean…

Plate 247

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Plate 3

Calcareous nannofossils from the Eocene North Alantic Ocean…

Plate 449

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Plate 5

Calcareous nannofossils from the Eocene North Alantic Ocean…

Plate 651

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Plate 7

Calcareous nannofossils from the Eocene North Alantic Ocean…

Plate 853

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Plate 9Calcareous nannofossils from the Eocene North Alantic Ocean…

Plate 1055

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Plate 11

Calcareous nannofossils from the Eocene North Alantic Ocean…

Plate 1257

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Plate 13

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Plate 1459

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Plate 15